Improvement in devices for propelling canal-boats



THOMAS K. M cDONELL. Improvement in Device for Propelling Canal Bo ats.

No*.125,205. Pa'tentedApr'|\2,1872. I

o G) v Vitness'es Inventor X I A UNITED STATES PATENT Orrrcn.

THOMAS K. MCDONELL, OF SAN FRANCISCO, CALIFORNIA.

IMPROVEMENT lN DEVICES FOR PROPELLING CANAL-BOATS.

Specification forming part of Letters Patent No. 125,205, dated April 2,1872.

SPECIFIGATIO N.

To all whom'it may concern:

Be it known that I, THOMAS K. MoDoNELL, ot' the city and county of SanFrancisco, State of California, have invented an Improved Device forPropelling Vessels; and I do hereby declare the following descriptionand accompanying drawing are suficient to enable any person skilled inthe art or science to which it most nearly appertains to make and use mysaid invention or improvements .without further invention or experiment.

My invention relates to a novel device for propelling vessels throughthe water, and is more particularly applicable for propellingcanal-boats. My device relates to wings or blades hinged at theextremity of a shaft which passes through the stern of the boat into thewater, and which is given a reciprocating motion from the interior ofthe vessel by any suitable power, so that the blades will be caused tofly open and take hold upon the water on the backward stroke, but willclose together on the reverse motion or stroke, so as to pass readilythrough the water without retarding the progress of the boat in anyconsiderable degree.

In order to more fully illustrate my invention, reference is had to theaccompanying drawing forming a part of this specification, in which-- Arepresents a vessel of any class. B is a shaft which extends from theinterior of the vessel through the stern and into the water, and isgiven a reciprocating motion by any suitable power inside the boat. Theouter extremity F of this shaft is made conical, as shown, and acup-shaped paddle or blade, 0, is hinged at each corner or angle of thetriangular head, so that they can open and close freely. The opening ofthe blades is limited by proper means, so that they will only open to aposition at right angles to the shaft where they will be in the bestposition for taking hold upon the water. A circular plate, D, is fixedto the end of the shaft B, which serves a double purpose: first, itprevents the hinged paddles from closing entirely on the reverse stroke,so that when the shaft is driven backward the water will have sufficienthold upon them to throw them open and, secondly, it serves, when theconcave paddles are open, as another paddle to aid in propelling theboat. The shaft B points downward from the stern of the boat, and itsmovement is consequently in that direction, so that upon the backstroke, when the paddles open and push against the water, they produceno surface agitation of any consequence. The movements of the shaft Bwill cause the paddles to open and close in accordance with thedirection in which it moves, the resistance of the water tending toclose the paddles on the reverse stroke, while it causes them to open onthe back or propelling stroke, thus giving great propelling power withsmall resistance to the forward motion of the boat. A similararrangement canbe placed in the bow of the boat, which can be protectedwith a housing of proper shape when not in use, so as to avoid anyresistance, in order to permit the boats being backed when necessary.

Owing to the peculiar shape of the head F of the shaft it is aprolongation of the planes of the blades 0 when they are closed, and itmerges into the shaft about on the lines of such prolongation. Thisconstruction allows of su-fficient room for hinging the blades on theend of the shaft, and at the same time greatly lessens the resistanceagainst the closed blades on the return stroke, as the blades andshaft-head together then form a cone, the apex dividing the water, andavoiding the loss of momentum in the vessel.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, lS

The shaft B, provided with the conicalshaped head F, and having theend-plate D fixed at its extremity, in combination with the hingedconcave blades or paddles G, substantially as and for the purpose abovedescribed.

In witness whereof I have hereunto set my hand and seal.

THOMAS K. MODONELL. [L. s.]

Witnesses:

J. L. BOONE,

J Aims H. DAVIS.

